1. Field of the Invention
The present invention relates to an information processing device suitable for processing big data at high speed.
2. Description of the Related Art
In the future, as demand of a big data analysis increases, a data amount handled by a calculator will explosively increase. On the other hand, the capacity of a DRAM incorporated in a calculator is limited. Therefore, a technique is desired which can store big data in an inexpensive and large capacity nonvolatile memory and enable a high speed analysis.
The large capacity nonvolatile memory has a data erase unit (block) larger than a data write unit, and therefore data cannot be overwritten. Further, in a conventional storage device using a nonvolatile memory, data which are unnecessary at different timings are mixed in the same block of the nonvolatile memory. Therefore, the storage device reads physically scattering necessary data from each block, erases the block from which the data has been read, and writes the read data back to the erased block. This process is called a garbage collection.
U.S. Pat. No. 7,254,668 B1 and U.S. Pat. No. 7,139,864 B2 disclose a technique, in a storage device using a nonvolatile memory, for classifying data based on a logical address and a write order of data and determining a data write target based on the classification.